One-way pump



y 5, 1970 T. SMITH 3,510,229

' ONE-I-WAY PUMP Filed July 23, 1968 IIIIII)I% k INVENTOR. Z5 77/0/7145 P. 5/7019 United States Patent Office 3,510,229 Patented May 5, 1970 3,510,229 ONE-WAY PUMP Thomas R. Smith, Newton, Iowa, assignor to The Maytag Company, Newton, Iowa, a corporation of Delaware Filed July 23, 1968, Ser. No. 746,835 Int. Cl. F04b 19/00; F04d 1/00, 29/02 US. Cl. 415-141 13 Claims ABSTRACT OF THE DISCLOSURE A one-way centrifugal pump utilizing a unitary impeller positioned within a pump chamber for rotation in either a pumping direction or in an opposite non-pumping direction. The impeller includes a central rotor portion and at least one blade, the rotor and blade being connected at a flexible connecting web portion adapted to maintain the blade in a substantially radial pumping position when the impeller is rotated in the pumping direction and to permit the collapse of the blade toward the rotor when the impeller is rotated in the non-pumping direction against the resistance of fluid in the chamber. The impeller is formed of material of sufficient flexibility to permit the web portion to bend with relative ease and of sufiicient rigidity so that the impeller will operate properly in the pumping position.

The present invention relates to improvements in pumping apparatus, and more specifically to an improved one-way centrifugal pump wherein a fluid impeller may be selectively driven in opposite directions of rotation, the impeller being eifective to pump fluid while rotating in one direction and relatively ineifective to pump fluid when rotating in the opposite direction.

Although one-way pumps have many applications, they are particularly useful in automatic clothes washing machines and in automatic dishwashers. In an automatic clothes washer, for example, it may be necessary to have a pump which operates during the spin cycle, but which is inoperative during the agitation or wash cycle. The motor is operated in one direction during the spin cycle, and in the opposite direction during the wash cycle. Rather than disengaging the pump during the agitation cycle, a one-Way pump is employed, which is ineffective when rotated by the motor during the wash cycle.

Automatic dishwashers normally include a recirculating pump along with a one-way drain pump with the impeller means of each pump being mounted on the shaft of a reversible electric motor. When the shaft rotates in one direction, the recirculating pump is effective to distribute water throughout the wash chamber, while the drain pump is essentially inoperative, avoiding the removal of fluid from the wash chamber. When the direction of rotation of the rotor shaft is reversed, the drain pump becomes operative to remove fluid from the wash chamber of the dishwasher.

While many one-way pump designs are familiar to those skilled in the art, they are often somewhat complex in design and expensive to manufacture. In addition, such pumps are frequently subject to breakdown as a result of the failure of the internal moving parts. The present invention overcomes these problems by providing a one-way pump having an impeller which may be formed of a unitary piece of material, and is of a simple design rendering it comparatively inexpensive to manufacture and trouble-free.

Generally, the present invention relates to a one-way centrifugal pump including a conventional pump body defining a pum chamber with an inlet opening and a peripheral outlet opening. Within the chamber, a umtary impeller is mounted for rotation in either a pumpmg direction or in an opposite, non-pumping direction. The impeller includes a rotor and at least one blade, together with a flexible connecting web portion formed at the base of the blade and adapted to maintain the blade 1n a substantially radial pumping position when the impeller is rotated in the pumping direction. The blade is urged into the radial position largely by the resistance of fluid in the chamber. The flexible connecting web portion also permits the blade to collapse toward the rotor when the impeller is rotated in the opposite, non-pumping direction when the chamber contains fluid.

The invention, its organization and method and operation, together with the objects and advantages thereof, will be best understood from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a cut away plan view of a preferred embodiment of the present invention, illustrating the pump impeller rotating in the pumping direction;

FIG. 2 is a cut away plan view of the apparatus shown in FIG. 1, but showing the impeller rotating in the opposite, non-pumping direction with the blades shown partially retracted;

FIG. 3 is a fragmentaiy plan view showing the flexible connecting web portion of the impeller assembly shown in FIG 2; and

FIG. 4 is a cross-sectional side elevation view of a second embodiment of the present invention.

Referring to the drawings, and particularly to FIG. 1, a one-way pump in accordance with the present invention is generally designated by reference numeral 10. The pump 10 includes a pump body 12 defining a pump chamber 14 of generally circular cross-sectional configuration, an inlet passage 16, and an outlet passage 18-. In the embodiment shown in FIGS. 1 and 2, the inlet passage 16 communicates with the pump chamber 14 at a peripheral inlet opening 20. The pump 10 includes a suitable mounting bracket 24 so that it may be anchored to an associated device (not shown) such as a clothes washer or dishwasher.

Within the chamber 14 a unitary impeller, generally indicated by reference numeral 26, is mounted on a shaft 28 for rotation in either a pumping direction, as shown in FIG. 1, or in a non-pumping direction, as shown in FIG. 2. The impeller 26 includes a central, generally cylindrical rotor portion 30 to which at least one and preferably a plurality of blades 32 are attached. As shown in FIG. 1, each blade 32 has a first face 34, which acts as the lead face when the impeller is rotated in the pumping direction, and a second face 36 which is opposite the first face.

Each blade 32 is connected to the rotor portion 30 by a flexible connecting web portion 38, shown in more detail in FIG. 3. The web portion 38 is adapted to maintain the blade 32 in a substantially radial pumping posi tion when the impeller 26 is rotated in a pumping direction against the resistance of fluid in the pump chamber 14 as shown in FIG. 1. When the impeller 26 is rotated in the opposite, non-pumping direction, as illustrated in FIG. 2, the web portion 38 permits the blade 32 to collapse toward the rotor 30, again provided that there is some fluid resistance within the chamber 14. To this end, as shown in FIG. 3, the web portion preferably comprises a relatively thin strip of flexible material formed at the base of the first face 34 of each blade 32. Opposite the flexible connecting web portion 38, at the base of the second face 36, the blades 32 are formed in an abutment portion 40 which is adapted to abut a corresponding abutment portion 42 on the rotor 30 to maintain the blade in a radial pumping position when the impeller is rotated in a pumping direction as shown in FIG. 1.

Referring again to FIG. 3, the impeller 26 is, in the most preferred embodiment, formed to define a substantially cylindrical cavity 44 at the base of each blade 32 between the web portion 38 and the abutment portions 40, 42 when the blade 32 is in the radial pumping position as illustrated in FIG. 1. The formation of such a substantially cylindrical portion 44 enlarges the area over which the web portion 38 extends and thus allows for bending over a larger area and improves its life.

FIG. 4 shows a second embodiment of the present invention wherein the inlet is axial and the outlet is radial. Parts which are substantially identical to those shown in FIGS. 1-3 are designated with like reference numerals. Referring in more detail to FIG. 4, the drawing shows a second one-way pump, generally indicated by reference numeral 60. The pump 60 has a pump body 62 forming a pump chamber 64, along with an inlet passage 66 which communicates with the pump chamber 64 at an axial inlet opening 68. As in the embodiment previously described, the pump shown in FIG. 4 has a peripheral outlet opening 22 communicating between the chamber 64 and a suitable outlet passage (not shown).

As also shown in FIG. 4, the one-way pump of the present invention incorporates a suitable seal assembly, generally indicated by reference numeral 70, as will be understood by those skilled in the art. This seal assembly 70 prevents the escape of fluid from the pump chamber 64. The shaft 28 is mounted for rotation within the pump chamber 64 by a suitable bearing assembly 72, and is driven by drive means (not shown) operating by a belt drive (not shown) to turn a pulley 74 which is secured to the shaft 28.

The operation of the one-way pump of the present invention is best appreciated by reference to FIGS. 1 and 2. When the impeller 26 rotates in a pumping direction, as shown in FIG. 1, the blade 32 will extend radially outwardly largely under the influence of the resistance to movement of the fluid within the chamber 14. The fluid is drawn in through the inlet passage 16, through the chamber 14, and out the outlet passage 22, as will be understood by those skilled in the art. Similarly, for the embodiment shown in FIG. 4, the fluid is drawn in through the inlet passage 66 and ejected at the outlet opening 22. When the pump is rotated in the opposite direction, as shown in FIG. 2, the fluid within the chamber 14 will tend to force the blades 32 against the rotor 30, so that very little pumping takes place. In both embodiments it is understood that rotation in the opposite or non-pumping direction causes rotation of the fluids within the pump chamber and thus a relatively small head is produced. A short standpipe or vertical run in the discharge passageway is provided to prevent flow with the relatively small head involved. In using the embodiment of FIG. 4 in a washing machine, for example, a standpipe can extend upwardly from the pump which is normally placed below the tub to a point several inches above the normal water level within the tub. A direct conduit from the bottom of the tub to the pump inlet is provided. Even with water in the tub in this arrangement, rotation in the opposite or non-pumping direction as during the agitation operation in the Washing machine will not pump water to drain through the standpipe. Reversal of rotation to the pumping direction during the extraction operation of the washing machine will effect pumping of the water from the tub through the standpipe to drain under the influence of the extended pumping blades.

A primary advantage of the one-way pump of the present invention is that the impeller 26 may be easily formed of a unitary piece of material. An essential characteristic of such a material is that it be suffieiently flexible to permit the relatively thin web portion 38 to bend easily, yet sufiiciently rigid to maintain an overall rigidity in the impeller 26, so that the blades 32 will operate properly in a radial pumping position as shown in FIG. 1. Suitable materials include polypropylene, polyethylene, Teflon (tetrafluoroethylene fluorocarbon resin), nylon, and the like. The most preferred material is polypropylene. It is preferred that the density of the impeller material be less than the density of the fluid being pumped so that in the non-pumping direction the centrifugal forces within the pumping chamber causes the blades to be directed inwardly. When for example, polypropylene is used as the impeller material in a water pumping system, the forces within the pump chamber while the impeller is being rotated in the opposite or non-pumping direction direct the blades inwardly in view of the differences in density, polypropylene being of lesser density than water.

Obviously, many modifications and variations of the invention as hereinbefore set forth will occur to those skilled in the art, and it is intended to cover in the appended claims all such modifications and variations as fall within the true spirit and scope of the invention.

What is claimed is:

1. A one-way centrifugal pump comprising: a pump body defining a pump chamber having an inlet opening and a peripheral discharge opening; a unitary impeller mounted within said chamber for rotation in a pumping direction and in an opposite non-pumping direction, said impeller including a rotor and at least one blade, said blade having a first face acting as the lead face when said impeller is rotated in said pumping direction and an opposite second face, said first face being substantially continuous and joined to said rotor at a base portion of said blade, said second face having a recess extending substantially across and partially through said blade whereby a flexible web portion is formed in said blade juxtaposed said first face; and means for maintaining said blade in a substantially radial pumping position when said impeller is rotated in said pumping direction against the resistance of fluid in said chamber, said web portion and said recess being cooperable for permitting said blade to col apse toward said rotor when said impeller is rotated in said non-pumping direction against the resistance of fluid in said chamber.

2. The one-way centrifugal pump as defined in claim 1 wherein said pump chamber has an axial inlet opening 3. The one-way centrifugal pump as defined in claim 1 wherein said pump chamber has a peripheral inlet opening.

4. The one-way centrifugal pump as defined in claim 1 wherein said flexible connecting web portion is formed at the base of said first face.

5. The one-way centrifugal pump as defined in claim 4 wherein said impeller is made of polypropylene.

6. A one-way centrifugal pump comprising: a pump body defining a pump chamber having an inlet opening and a peripheral discharge opening; an impeller formed from a unitary piece of material and mounted within said chamber for rotation in a pumping direction and in an opposite non-pumping direction, said impeller including a central rotor and a plurality of blades each having a first face acting as the lead face when said impeller is rotated in said pumping direction and an opposite second face, and said impeller including a flexible connecting web portion formed at the base of said first face and an abutment portion formed opposite said web portion at the base of said second face, said abutment portion adapted to abut a corresponding abutment portion on said rotor to maintain said blade in a substantially radial pumping position when said impeller is rotated in said pumping direction against the resistance of fluid in said chamber, and said web portion adapted to permit said blade to collapse toward said rotor when said impeller is rotated in said non-pumping direction against the resistance of fluid in said chamber.

7. The one-way centrfugal pump as defined in claim 6 wherein said pump chamber has an axial inlet opening.

8. The one-way centrifugal pump as defined in claim 6 wherein said pump chamber has a peripheral inlet opening.

9. The one-way centrifugal pump as defined in claim 6 wherein said material is polypropylene.

10. The one-way centrifugal pump as defined in claim 6 wherein said impeller defines a substantially cylindrical cavity at the base of each blade between said web portion and said abutment portion when said blade is in said pumping position.

11. The one-way centrifugal pump as defined in claim 10 wherein said material is polypropylene.

12. A one-way centrifugal pump comprising: a pump body defining a pump chamber having an inlet opening and a peripheral discharge opening; an impeller formed from a unitary piece of material and mounted within said chamber for rotation in a pumping direction and in an opposite non-pumping direction, said impeller including a central rotor and a plurality of blades each having a first face acting as the lead face when said impeller is rotated in said pumping direction and an opposite second face, and said impeller including a flexible connecting web portion formed at the base of said first face and an abutment portion formed opposite said web portion at the base of said second face, said abutment portion adapted to abut a corresponding abutment portion on said rotor to maintain said blade in a substantially radial pumping position when said impeller is rotated in said pumping direction against the resistance of fluid in said chamber; and said web portion adapted to permit said blade to collapse toward said rotor when said impeller is rotated in said non-pumping direction against the resistance of fluid in said chamber; a rotatable shaft affixed to said impeller at the center of rotation; seal means for preventing the escape of fluid from said chamber; and drive means for selectively rotating said shaft and said impeller in said pumping direction and in said non-pumping direction.

13. A differential-pumping centrifugal pump comprising: a pump body defining a pump chamber having an inlet opening and a peripheral discharge opening; a unitary impeller mounted within said chamber for rotation in a. first direction for a first pumping rate and in a second direction for a second lower pumping rate, said impeller including a rotor and at least one blade, said blade having a first face acting as the lead face when said impeller is rotated in said first pumping direction and an opposite second face; means formed in said blade for permitting hinged movement of said first face toward said rotor when said impeller is rotated in said second direction against the resistance of fluid in said chamber; and abutment means juxtaposed said second face for maintaining said blade in a substantially radial pumping position when said impeller is rotated in said first pumping direction against the resistance of fluid in said chamber.

References Cited UNITED STATES PATENTS 2,570,862 10/1951 Rosenkrans et a1. 103-97 1,883,634 10/1932 Easton 103--96 2,669,188 2/1954 McIntyre 103-115 2,671,408 3/ 1954 Kreitchman 103-115 3,054,355 9/1962 Neely 103--117 3,382,812 5/1968 Smith 103-216 FOREIGN PATENTS 662,032 7/1938 Germany.

HENRY F. RADUAZO, Primary Examiner US. Cl. X.R. 

